Invalidate border/outline on color change only if they use current color

third_party/WebKit/Source/core/layout/LayoutObject.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2000 Dirk Mueller (mueller@kde.org)
  *           (C) 2004 Allan Sandfeld Jensen (kde@carewolf.com)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2011 Apple Inc.
  *               All rights reserved.
  * Copyright (C) 2009 Google Inc. All rights reserved.
  * Copyright (C) 2009 Torch Mobile Inc. All rights reserved.
  *               (http://www.torchmobile.com/)
@@ skipping 1525 matching lines @@
 
   // TODO(wangxianzhu): We may avoid subtree paint invalidation on CSS clip
   // change for SPv2.
   if (diff.CssClipChanged())
     diff.SetNeedsPaintInvalidationSubtree();
 
   // Optimization: for decoration/color property changes, invalidation is only
   // needed if we have style or text affected by these properties.
   if (diff.TextDecorationOrColorChanged() &&
       !diff.NeedsFullPaintInvalidation()) {
-    if (Style()->HasBorder() || Style()->HasOutline() ||
+    if (Style()->HasBorderColorReferencingCurrentColor() ||

[wkorman, 2017/04/24 22:05:41]

Could add unit tests for this, BorderData, and ComputedStyle (in separate
*Test.cpp each). Would be trivial tests but I think nice to start building them
up. BorderDataTest does not exist but the others do.

Layout test obviously covers end behavior.

[Xianzhu, 2017/04/24 22:36:48]

Added ComputedStyleTest.HasOutlineWithCurrentColor and
ComputedStyleTest.HasBorderColorReferencingCurrentColor. Not BorderDataTest
because ComputedStyle controls how BorderData mutates. Using friend test would
just exposes BorderData as a struct and the tested code is too different from
actual executed code.

+        Style()->IsOutlineColorCurrentColor() ||
         Style()->HasBackgroundRelatedColorReferencingCurrentColor() ||
         // Skip any text nodes that do not contain text boxes. Whitespace cannot
         // be skipped or we will miss invalidating decorations (e.g.,
         // underlines).
         (IsText() && !IsBR() && ToLayoutText(this)->HasTextBoxes()) ||
         (IsSVG() && Style()->SvgStyle().IsFillColorCurrentColor()) ||
         (IsSVG() && Style()->SvgStyle().IsStrokeColorCurrentColor()) ||
         IsListMarker())
       diff.SetNeedsPaintInvalidationObject();
   }
@@ skipping 2096 matching lines @@
     const blink::LayoutObject* root = object1;
     while (root->Parent())
       root = root->Parent();
     root->ShowLayoutTreeAndMark(object1, "*", object2, "-", 0);
   } else {
     WTFLogAlways("%s", "Cannot showLayoutTree. Root is (nil)");
   }
 }
 
 #endif